tests: match stream error messages with and without the path

PHP 8.6 removed the path parameter from the stream error functions
(php/php-src#22792, merged as 34c686a5b4e), so warnings are now emitted
as "readfile(): Failed to open stream" instead of
"readfile(<url>): Failed to open stream". php-src updated 30 of its own
.phpt files the same way, so this is intentional, not a regression.

Use %S (zero or more non-newline characters) inside the parentheses so
the expectation matches both the pre-8.6 and 8.6+ output, keeping the
test working across all supported PHP versions.

--- a/tests/streams_7.phpt
+++ b/tests/streams_7.phpt
@@ -15,8 +15,8 @@
 --EXPECTF--
 Warning: readfile(): https:// wrapper is disabled in the server configuration by allow_url_fopen=0 in %s
 
-Warning: readfile(https://github.com/kjdev/php-ext-zstd/raw/master/tests/streaming.zst): %sailed to open stream: no suitable wrapper could be found in %s
+Warning: readfile(%S): %sailed to open stream: no suitable wrapper could be found in %s
 
-Warning: readfile(compress.zstd://https://github.com/kjdev/php-ext-zstd/raw/master/tests/streaming.zst): %sailed to open stream: operation failed in %s
+Warning: readfile(%S): %sailed to open stream: operation failed in %s
 
 ===Done===